CN218653860U - Dynamic mixer for enhancing gas mixing in selective catalytic reduction reactor - Google Patents

Abstract

The utility model relates to a selective catalytic reduction reactor, concretely relates to reinforcing selective catalytic reduction gas mixing's dynamic mixer, the ammonia injection grid of inversion in the dynamic mixer includes the flue, set up at a plurality of dwangs of ammonia injection grid below, rotate a plurality of unpowered wind balls of connection on the dwang, the dwang direction of arrangement is perpendicular with the ammonia injection pipe arrangement direction of ammonia injection grid, unpowered wind ball position is under the ammonia injection mouth. The utility model discloses dynamic mixer has solved the inhomogeneous problem of gas mixture among the selective catalytic reduction reactor, has reduced kinetic energy loss and loss of pressure, optimizes ammonia and flue gas mist speed size simultaneously, makes the velocity distribution of mist before getting into the catalyst layer more reasonable and even.

Description

Dynamic mixer for enhancing gas mixing in selective catalytic reduction reactor

Technical Field

The utility model relates to a selective catalytic reduction reactor, concretely relates to dynamic mixer that reinforcing selective catalytic reduction gas mixes.

Background

A Selective Catalytic Reduction (SCR) flue gas denitration method refers to a technology that a reducing agent selectively reacts with nitrogen oxides in flue gas in the presence of a catalyst and oxygen within a certain temperature range to reduce the nitrogen oxides into nitrogen gas and water so as to reduce the emission of the nitrogen oxides. The Selective Catalytic Reduction (SCR) denitration method has the characteristics of high efficiency and mature technology, so that the highest denitration efficiency can reach over 90 percent at present, and the SCR denitration method is widely applied in the world. At present, most domestic coal-fired thermal power plants adopt the technology to meet the emission requirements, but some aspects needing improvement still exist in the process of using a selective catalytic reduction denitration method. The mixing condition of the flue gas and the reducing agent (such as ammonia gas and the like) has a certain influence on the denitration efficiency and the ammonia escape condition, if the flue gas and the ammonia gas are not uniformly mixed, the ammonia escape is increased in an area with high reducing agent concentration, and the ammonia (NH) is caused ₃ ) Sulfur trioxide (SO) with flue gas ₃ ) Reacts with water to form ammonium bisulfate (NH) ₄ HSO ₄ ) The cold section of the air preheater is strongly corroded, and the ammonia gas concentrationThe low-area denitration efficiency is low. Therefore, the enhancement of the gas mixing in the selective catalytic reduction reactor has important significance for improving the denitration efficiency and reducing the damage to equipment. In addition, the velocity magnitude and the velocity distribution of the mixed gas of flue gas and reducing agent when getting into the catalyst can also produce certain influence to denitration efficiency, if speed is too fast, then can cause the mixed gas to be short at catalyst layer dwell time, and then lead to chemical reaction time shorter, reduce denitration efficiency. In addition, if the speed of the mixed gas is too high when the mixed gas enters the catalyst layer, a certain impact is caused on the catalyst layer, and further, the loss of the catalyst is increased. If the velocity of the mixed gas is too low, ash deposition tends to occur in the catalyst layer, and the catalyst layer is clogged.

At present, a static mixer is mostly adopted for enhancing the mixing of the flue gas and the reducing agent in the selective catalytic reduction reactor, and the optimization of the static mixer is mostly optimized by changing the shape of the static mixer. Although the existing static mixer can increase the mixing of the flue gas and the reducing agent to a certain extent, further improve the denitration efficiency and reduce the escape of ammonia, certain defects still exist in certain aspects: the mixing degree of the reducing agent and the flue gas is not high, so that the denitration efficiency and the ammonia escape rate cannot reach a better state; in addition, due to the blockage of the static mixer, a large pressure loss can be formed in the fluid in the denitration system before and after the static mixer; finally, because the static mixer is fixed in the denitration device, parameters such as deflection angle and the like cannot be changed at will, the parameters of the static mixer cannot be adjusted correspondingly according to the change of the flue gas inlet conditions caused by different working conditions of the boiler.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects, the utility model aims to provide a dynamic mixer that reinforcing selective catalytic reduction gas mixes has solved the uneven problem of gas mixture among the selective catalytic reduction reactor, has reduced kinetic energy loss and loss of pressure, optimizes ammonia and flue gas mist velocity size simultaneously, makes the velocity distribution of mist before getting into the catalyst layer more reasonable and even.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a developments blender that reinforcing selective catalytic reduction gas mixes, includes that the ammonia injection grid of invering in the flue, a plurality of dwangs, the rotation of setting in ammonia injection grid below connect a plurality of unpowered wind balls on the dwang, the dwang is arranged the ammonia injection pipe arrangement direction of direction and ammonia injection grid and is perpendicular, unpowered wind ball position is located under the ammonia injection mouth.

Preferably, the number of the unpowered air balls is equal to that of the ammonia spraying openings, and the unpowered air balls correspond to the ammonia spraying openings in position one to one.

Preferably, the dwang both ends are rotated with the flue wall and are connected, flue wall outside still sets up a plurality of external motors, and every external motor output shaft is connected with a dwang.

Preferably, the external motor is a generator motor.

The utility model discloses an actively beneficial effect:

1. the utility model discloses the arrangement of ammonia injection grid has carried out certain change in the conventional ammonia injection grid arrangement, and under the arrangement of conventional ammonia injection grid, the injection direction of ammonia was unanimous with the flow direction of flue gas, but the mixed situation of ammonia and flue gas is relatively poor, the utility model discloses another kind of ammonia injection grid arrangement has been taken, even the ammonia sprays the flow opposite direction of direction and flue gas, strengthens the disturbance between gas, and then strengthens the mixture of ammonia and flue gas, has compared and has obtained certain improvement in the aspect of the gas mixing in conventional mode. But because make ammonia injection direction and flue gas flow opposite direction, can cause great kinetic energy loss and pressure loss, great kinetic energy loss and pressure loss for reducing this kind of ammonia injection grid arrangement mode and lead to, the utility model discloses dynamic mixer comprises the unpowered wind ball of a plurality of, and there is the flabellum on unpowered wind ball surface, and the size of unpowered wind ball is decided according to selective catalytic reduction reactor size of dimensions and ammonia injection grid, and dynamic mixer is located ammonia injection grid below, and for the opposite direction of flue gas flow promptly, unpowered wind ball is located certain distance department under the ammonia injection mouth, and its unpowered distance length is decided according to the size of ammonia injection mouth and the actual conditions of ammonia injection speed, and a set of exhaust ball is connected on same dwang. The unpowered air ball has the advantages that no matter which direction the gas flows, the unpowered air ball can rotate along the same direction, and the unpowered air ball is very suitable for the flow field situation that the ammonia spraying direction is opposite to the smoke flowing direction. The utility model discloses dynamic mixer makes the kinetic energy of ammonia that spouts the ammonia grid and spray obtain abundant utilization under the condition of not losing flue gas kinetic energy basically, can effectively solve and lead to kinetic energy loss and loss of pressure's problem owing to make to spout the ammonia direction and change, and rotation through unpowered wind ball moreover can further strengthen the disorderly condition in flow field, makes the mixed condition of flue gas and ammonia further strengthen.

2. The utility model discloses arrange a small-size external motor at every round bar end, control the rotational speed of the whole unpowered wind ball of group, through the rotational speed of the unpowered wind ball of external motor control every group, both can be through the rotational speed that increases all unpowered wind balls, and then increase the kinetic energy and the mist mixed condition of mist, also can be through the rotational speed that reduces all unpowered wind balls, and then reduce the velocity of flow of mist, make the mist can keep in reasonable within range at the speed before reacing the catalyst layer. In addition, for the condition that the operation condition of the generator set is changed to cause the change of the flow of the inlet flue gas, the external motor of the dynamic mixer can increase or reduce the flow speed of the mixed gas by consuming external energy, so that the speed of the mixed gas before entering the catalyst layer is kept in a reasonable range.

3. The utility model discloses external motor is generator motor, if unpowered wind ball rotational speed is too big, need reduce its rotational speed, then the generator part among the accessible generator motor turns into its kinetic energy into the electric energy, store unnecessary energy in the rotational speed that reduces unpowered wind ball, and the electric energy of storage is under the condition that unpowered wind ball rotational speed was crossed lowly, the motor part through generator motor turns into the kinetic energy of unpowered wind ball again, strengthen its rotational speed, further reduce the energy loss of a whole set of device.

4. Because the ammonia injection grid is inverted, the smoke and particles in the smoke directly impact the nozzle, and further the nozzle is likely to be abraded or blocked, but the dynamic mixer can effectively reduce the problems, because an unpowered wind ball is arranged below each ammonia injection port, the unpowered wind ball can effectively avoid the smoke and the particles from directly impacting the ammonia injection port, and further the abrasion and the blockage of the ammonia injection port are reduced; moreover, because the inverted ammonia spraying grid and the dynamic mixer can effectively promote the mixing of the flue gas and the reducing agent, the number of the ammonia spraying openings can be properly reduced, the area of the ammonia spraying openings is properly increased, and the problem of blockage of the ammonia spraying openings can be reduced to a certain extent.

Drawings

FIG. 1 is a schematic diagram of a dynamic mixer for enhanced mixing of selective catalytic reduction gases according to the present invention;

FIG. 2 is a schematic view of the structure of the unpowered wind ball of the present invention;

in the figure: 1-ammonia spraying grid, 2-flue, 3-unpowered air ball, 4-rotating rod, 5-external motor, 6-ammonia spraying port, 7-flue wall, 8-ammonia spraying pipe and 9-fan blade.

Detailed Description

The invention will be further described with reference to some specific embodiments.

Example 1

Fig. 1 and 2 show a dynamic mixer for enhancing selective catalytic reduction gas mixing, which comprises an inverted ammonia injection grid 1 in a flue 2 of an SCR flue gas denitration method, a plurality of rotating rods 4 arranged below the ammonia injection grid 1, and a plurality of unpowered air balls 3 rotatably connected to the rotating rods 4, wherein only 6 ammonia injection pipes are arranged on the flue at equal intervals, six unpowered air balls are arranged on each rotating rod 4, the ammonia injection grid is inverted, the ammonia injection direction is opposite to the flue gas flowing direction, the rotating rods 4 are cylindrical rods, the rotating rods 4 extend to the outer side of a flue wall 7, the arrangement direction of the rotating rods 4 is perpendicular to the arrangement direction of the ammonia injection pipes 8 of the ammonia injection grid, the unpowered air balls 3 can rotate on the rotating rods 4 but do not move left and right, the unpowered air balls 3 are positioned under an ammonia injection port 6 of the ammonia injection grid 1, the unpowered air balls 3 adopt a common unpowered air ball structure, the air balls are unpowered, a plurality of arc-shaped fan blades 9 are arranged on the surface of the unpowered air balls 3, the fan blades 9 of the unpowered air balls 3 incline towards the same direction, the flue gas and the fan blades are pushed by the flow of the flue gas, the air balls 3, the loss caused by the basic kinetic energy of the ammonia injection grid and the kinetic energy loss caused by the effective utilization of the kinetic energy loss of the ammonia injection.

Further, the number of the unpowered air balls 3 is equal to the number of the ammonia spraying openings 6, the positions of the unpowered air balls correspond to the positions of the ammonia spraying openings one by one, the unpowered air balls 3 are arranged under each ammonia spraying opening 6, and the number of the rotating rods is consistent with the number of the ammonia spraying openings in each ammonia spraying pipe.

Further, dwang 4 both ends are rotated with flue wall 7 and are connected, flue wall 7 outside still sets up a plurality of external motors 5, every external motor 5 output shaft is connected with a dwang 4, the direction of rotation of dwang 4 is unanimous with the direction of rotation of flue gas and ammonia driven unpowered wind ball 3, every external motor 5 control the rotational speed of the unpowered wind ball on the whole group dwang 4, one end of every dwang 4 all arranges by an external motor 5, control all relatively independent to its unpowered wind ball group rotational speed, through the rotational speed of every unpowered wind ball group of motor differentiation control group, can optimize the velocity distribution of mist before getting into the catalyst layer to a certain extent, be particularly useful for generating set operation condition and take place the flue that changes.

Furthermore, the external motor 5 is a generator motor, if the rotation speed of the unpowered wind ball is too high and needs to be reduced, the kinetic energy of the unpowered wind ball can be converted into electric energy through a generator part in the generator motor, the rotation speed of the unpowered wind ball is reduced while the surplus energy is stored, and the stored electric energy is converted into the kinetic energy of the unpowered wind ball again through the motor part of the generator motor under the condition that the rotation speed of the unpowered wind ball is too low, so that the rotation speed of the unpowered wind ball is enhanced, and the energy loss of the whole set of device is further reduced.

Application test: will the utility model discloses dynamic mixer is used for certain coal-fired thermal power plant, and the cross sectional dimension of ammonia injection grid place flue is 2 mx 10m, and the flue gas flow velocity is 15 ms, equidistantly arranges 24 on the flue and spouts the ammonia pipe, and per two ammonia pipe intervals of spouting are 0.4m, and equidistantly open 6 on every ammonia pipe of spouting spouts the ammonia mouth, and every two ammonia mouth intervals of spouting are 0.28m on spouting the ammonia pipe with the root, and every diameter of spouting the ammonia mouth is 6mm, spouts 144 ammonia mouths altogether, and it is 25 ms to spout ammonia speed. Unpowered wind ball is located ammonia spraying mouth below 0.5m department, and according to ammonia spraying mouth's quantity, size of a dimension and arrangement mode in the ammonia spraying grid, adopt 144 unpowered wind balls altogether, the diameter of every unpowered wind ball is 30mm, adopts 6 dwang and 6 motors, and the interval of every two dwang is 0.28m, has 24 unpowered wind balls on every dwang, and the interval of every two unpowered wind balls on the same dwang is 0.4m.

The utility model discloses dynamic mixer during operation, when the dynamic mixer of flowing through of flue gas, can drive every unpowered wind ball 3 fast rotation in the dynamic mixer, when every ammonia that spouts 6 sprays in the ammonia grid 1 flows through the dynamic mixer, also can make every unpowered wind ball 3 fast rotation that spouts 6 corresponds in the ammonia mouth in the dynamic mixer, no matter be flue gas or ammonia can all make every unpowered wind ball 3 rotate along same direction in the dynamic mixer 2, and increase the disturbance in 2 interior flow fields of flue, make the mixed degree of flue gas and ammonia increase. And simultaneously, according to the actual condition of the flow speed of the flue gas at the inlet of the selective catalytic reduction reactor, all external motors 5 are controlled in real time, so that the rotating speed of all unpowered air ball groups is controlled, and the overall flow speed of the mixed gas in the flue is reasonably controlled. In addition, each external motor 5 is controlled in a differentiated mode according to the speed distribution before entering the catalyst layer, the rotating speed of each unpowered air ball group is adjusted, and the purpose of optimizing the speed distribution of the mixed gas is achieved.

The utility model discloses a mode of will spouting the ammonia grid inversion makes the injection direction of ammonia and the flow opposite direction of flue gas, can strengthen the mixture of flue gas and ammonia to a certain extent, to solving because of flue gas and ammonia mix uneven and lead to causing the ammonia escape phenomenon in the high region of ammonia concentration, and can cause the inefficiency scheduling problem of denitration to have certain positive effect in the region that ammonia concentration is low. However, if the ammonia injection grid is inverted singly, although a certain denitration efficiency can be improved, the ammonia injection direction is reversed, so that certain kinetic energy and pressure loss are caused, and the pressure loss in the reactor cannot be kept in a reasonable range. The utility model discloses take a dynamic mixer to replace former static mixer, can not only further strengthen the disturbance of flue gas and ammonia, the mixed degree of reinforcing flue gas and ammonia also can fully reduce the kinetic energy loss that the ammonia sprays reverse change and leads to. In addition, by means of an external motor, the mixing degree of the mixed gas can be further enhanced by consuming external energy under the condition of demand. In addition, can increase the velocity of flow of mist through external motor, make the selective catalytic reduction reactor satisfying under the condition of loss of pressure in certain extent, can arrange with many water conservancy diversion and fairing, promote mist velocity distribution before getting into the catalyst layer more reasonable and even, in addition with the rotational speed of every group's unpowered wind ball group in the differentiation adjustment dynamic mixer, the velocity distribution that can further optimize mist is more even, partial region speed is too slow when avoiding getting into the catalyst layer, partial region speed is too fast and lead to catalyst deposition and catalyst wearing and tearing, and then lead to the denitration inefficiency. And under the condition that the generating set of the thermal power plant needs to operate under variable working conditions, the condition that the speed of mixed gas caused by the change of the speed of inlet flue gas in the selective catalytic reduction reactor cannot reach a reasonable range can be optimized in real time through an external motor in the dynamic mixer.

Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited, and other modifications or equivalent replacements made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims (4)

1. The utility model provides a developments blender that reinforcing selective catalytic reduction gas mixes, its characterized in that, including the ammonia injection grid of invering in the flue, set up a plurality of dwangs, the unpowered wind ball of rotation connection on the dwang in ammonia injection grid below, the dwang is arranged the direction and is arranged the direction perpendicular with the ammonia injection pipe of ammonia injection grid, unpowered wind ball position is located under the ammonia spout.

2. The dynamic mixer of claim 1, wherein the number of the unpowered air balls is equal to the number of the ammonia injection ports, and the unpowered air balls are in one-to-one correspondence with the ammonia injection ports.

3. The dynamic mixer for enhancing mixing of selective catalytic reduction gases according to claim 1 or 2, wherein both ends of the rotating rod are rotatably connected with the flue wall, a plurality of external motors are further arranged outside the flue wall, and an output shaft of each external motor is connected with one rotating rod.

4. The dynamic mixer of enhanced selective catalytic reduction gas mixing according to claim 3, wherein the external electrical machine is a generator motor.

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